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Rinaldo Poli

Publications and source records attributed to Rinaldo Poli.

21 records · Page 2Linked to original sources
PubMed1997

H(+)/AuPPh(3)(+) Exchange for the Hydride Complexes CpMoH(CO)(2)(L) (L = PMe(3), PPh(3), CO). Formation and Structure of [Cp(CO)(2)(PMe(3))Mo(AuPPh(3))(2)](+)[BF(4)](-).

The reaction of CpMoH(CO)(2)L with AuPPh(3)(+)BF(4)(-) in THF at -40 degrees C proceeds directly to the MoAu(2) cluster compounds [CpMo(CO)(2)L(AuPPh(3))(2)](+)BF(4)(-) (L = PMe(3) (1), PPh(3) (2)) with release of protons. A 1:1 reaction leaves 50% of the starting hydride unreacted. At lower temperature, however, the formation of a [CpMo(CO)(2)(PMe(3))(&mgr;-H)(AuPPh(3))](+) intermediate is observed. This compound evolves to the cation of 1 and CpMoH(CO)(2)(PMe(3)) upon warming and is deprotonated by 2,6-lutidine to afford CpMo(CO)(2)(PMe(3))(AuPPh(3)). The X-ray structure of 1 can be described as a four-legged piano stool with the PMe(3) and the "eta(2)-(AuPPh(3))(2)" ligands occupying relative trans positions. [Cp(CO)(2)(PMe(3))Mo(AuPPh(3))(2)](+)[BF(4)](-) (M(r) = 1298.41): monoclinic, space group P2(1)/n, a = 18.1457(13) Å, b = 9.7811(7) Å, c = 26.096(2) Å, beta = 105.086(5) degrees, V = 4472.0(5) Å(3), Z = 4. The reaction of CpMoH(CO)(2)(PMe(3)) with 3 equiv of AuPPh(3)(+) affords a MoAu(3) cluster, [CpMo(CO)(2)(PMe(3))(AuPPh(3))(3)](2+) (3), in good yields under kinetically controlled conditions. Under thermodynamically controlled conditions, 3 dissociates extensively into 1 and free AuPPh(3)(+). It is proposed that the hydride ligand helps build higher nuclearity Mo-Au clusters. The difference in reaction pathways for the interaction of AuPPh(3)(+) with CpMoH(CO)(2)L when L = PR(3) or CO and for the interaction of CpMoH(CO)(2)(PMe(3)) with E(+) when E = H, Ph(3)C or AuPPh(3) is discussed. The lower acidity and greater aurophilicity of the [CpMo(CO)(2)L(&mgr;-H)(AuPPh(3))](+) intermediate when L = PMe(3) favor attack by AuPPh(3)(+) before deprotonation.

Journal Article↗
PubMed1996

Anionic Halomolybdate(III) Chemistry. Tetrahydrofuran Loss from [MoX(3)Y(THF)(2)](-) (X, Y = Cl, Br, I), Preparation and Properties of [Mo(3)X(12)](3)(-) (X = Br, I), and Crystal Structure of the Edge-Sharing Trioctahedral [PPh(4)](3)[Mo(3)I(12)].

By interaction of MoX(3)(THF)(3) with [Cat]X in THF, the salts [Cat][MoX(4)(THF)(2)] have been synthesized [X = I, Cat = PPh(4), NBu(4), NPr(4), (Ph(3)P)(2)N; X = Br, Cat = NBu(4), PPh(4) (Ph(3)P)(2)N]. Mixed-halide species [MoX(3)Y(THF)(2)](-) (X, Y = Cl, Br, I) have also been generated in solution and investigated by (1)H-NMR. When the tetraiodo, tetrabromo, and mixed bromoiodo salts are dissolved in CH(2)Cl(2), clean loss of all coordinated THF is observed by (1)H-NMR. On the other hand, [MoCl(4)(THF)(2)](-) loses only 1.5 THF/Mo. The salts [Cat](3)[Mo(3)X(12)] (X = Br, I) have been isolated from [Cat][MoX(4)(THF)(2)] or by running the reaction between MoX(3)(THF)(3) and [Cat]X directly in CH(2)Cl(2). The crystal structure of [PPh(4)](3)[Mo(3)I(12)] exhibits a linear face-sharing trioctahedron for the trianion: triclinic, space group P&onemacr;; a = 11.385(2), b = 12.697(3), c = 16.849(2) Å; alpha = 76.65(2), beta = 71.967(12), gamma = 84.56(2) degrees; Z = 1; 431 parameters and 3957 data with I > 2sigma(I). The metal-metal distance is 3.258(2) Å. Structural and magnetic data are consistent with the presence of a metal-metal sigma bond order of (1)/(2) and with the remaining 7 electrons being located in 7 substantially nonbonding orbitals. The ground state of the molecule is predicted to be subject to a Jahn-Teller distortion, which is experimentally apparent from the nature of the thermal ellipsoid of the central Mo atom. The [Mo(3)X(12)](3)(-) ions reacts with phosphines (PMe(3), dppe) to form products of lower nuclearity by rupture of the bridging Mo-X bonds.

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